At which region of DNA are the sister chromatids of chromosomes joined together?

The sister chromatids of chromosomes are joined at the centromere, a constricted region of the chromosome. Each chromatid forms one half of a duplicated chromosome, which has been replicated in preparation for cell division. During cell division, the two sister chromatids are pulled to opposite sides of the cell by spindle fibers that attach to the centromere. The cell divides into two soon after, resulting in two identical daughter cells.